In primate patients undergoing diagnostic and surgical procedures for ischemic heart disease, the assessment of myocardial ischemia is crucial to their safe management. The onset of angina in awake or unsedated patients is a clear indication of ischemia. This indication is not available in patients under sedation or anesthesia. It is to the patient's benefit to prevent situations where the myocardial metabolic requirements exceed the coronary circulation's ability to meet them.
Separate blood pressure monitors and heart rate monitors are used in the operating room to provide instant and continuous readings of the patinet's blood pressure and pulse rate. These separate readings of information relative to the patient's blood pressure and heart rate are mentally combined by the personnel in the operating room to provide rate pressure product information. The rate pressure product information informs the surgeon of myocardial oxygen consumption. The monitoring of the rate pressure product information provides a warning of dangerous increases of myocardial consumption leading to myocardial ischemia or infarction. The rate pressure product mental calculation is periodically made and at times when the operating room personnel are performing critical procedures. Being a mental calculation, it is subject to human error.